Dosage: Usual Adult Dose for Bronchitis: 250 to 500 mg orally three times a day for 1 week. Usual Adult Dose for Otitis Media: 250 to 500 mg orally three times a day for 10 to 14 days. Usual Adult Dose for Pneumonia: 500 mg orally three times a day for 2 to 3 weeeks.